My carbon Milan 4.2 build

Worked on the front seat mount tonight.

This shows what I'm trying to do: I'd like (adjustable) straps, detachable, just like in my Snoek (and in many vm's these days).
IMG_20260706_205131.jpg
But, the original 'rollbar' is about as stiff as a noodle, so I could not hang the front seat from that (nor would it actually have any safety function....). I also did not like the sharp edges on front and back of this rollbar.
IMG_20260706_211850.jpg
So I cut some 4mm foam board, and stuck that to the inside of it. This foam is just flexible enough to make this bend :cool:
It took a few tries to get the pattern correct. I need it to be 1 piece, so that it would follow the curve smoothly.
IMG_20260707_213838.jpg
And I added some strips to lie in the step/gutter, to add some more thickness to these edges.
The inside foam panel extends down below the rollbar and then bends to both sides of the body, and attaches to the stiffening beam that I glued in there already. Added some small foam panels to close the (front/rear) holes. This box should add a ton of stiffness.
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You can also see the threaded rivet I put in this aluminium plate, this will be my seat strap anchor point.
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I then mixed epoxy with a LOT of fenol microballoons to create a lightweight filler paste, to smooth it all out.
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After curing and some sanding I will laminate over this, to turn it into a really stiff and strong rollbar with nicely rounded edges and integrated seat strap anchors. :cool: I'll add some kevlar to this rollbar too, for safety

I was hoping to have actually laminated tonight, but making the foam stuff took longer than I thought.
But, on the plus-side, it also turned out prettier than I thought it might, so I'm still happy.
 
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Look at my pictures again Flowi, it's not thát hard to see ;)
The piece of aluminium is a load spreader. To take the point load of the screw and spread it over a large area of carbon.

Ok, so I sanded the paste.
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Another picture from the inside (showing also a little bit of aluminium (top of picture), this shows how I'm connecting the rollbar to the central stiffening beam, makinjg it 1 box:
IMG_20260708_083223.jpg
Soft/round edge (and seat anchor point)
IMG_20260708_083837.jpg
Time to cover it all up.
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Next picture shows a small piece of the Kevlar/Carbon hybrid UD that's below the carbon. It runs vertically, to maximize stiffness and provide safety. It also wraps around the front edge.
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It unfortunately does add some thickness that can be seen through the carbon on this picture:
IMG_20260708_094455.jpg
The other side will have to wait until this has cured enough, as the bike is now at 45 degrees to this side.
 
Arend-Jan schrieb:
Look at my pictures again Flowi, it's not thát hard to see ;)
The piece of aluminium is a load spreader. To take the point load of the screw and spread it over a large area of carbon.
Zum Vergrößern anklicken....
Ah thanks for the clarification. I thought the metal piece was a steel Tee Nut and that you had inserted that into some aluminum plate. Sometimes I misinterpret something and then it's hard to snap out :D
 
Did you lay the new carbon of the roll bar just on top of the lacquer and clear coat? Does that give proper adhesion?
 
flowi schrieb:
Did you lay the new carbon of the roll bar just on top of the lacquer and clear coat? Does that give proper adhesion?
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Given how the part lines look, it’s either primer, or it might be gel coat. Most Velomobiles used to be gel coated. However, gel coat requires the molds to be perfect because the gel coat is the first thing in the mold. in recent years all but Katanga switched to paint. That way they can cover the shell with auto body filler which smooths imperfections and eliminates the pits in the epoxy that could lead to a bad paint job. It’s more labor intensive though.
 
flowi schrieb:
I re-read the post multiple times but I don't see an answer. Maybe you interpret image 3 in that post as that he completely sanded down the original roll bar?
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Would't it be save to assume, seeing multiple instances in the quality of work and thought that went into building the 4.2 so far, that @Arend-Jan knows what he ist doing? Even if you (or me) don't understands every single part of it?
 
Front seat mounts
IMG_20260709_195834.jpg
fore/aft adjustable and hinged
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Put the pivot in front and above the front screw, so that the seat can hinge flat onto the floor and still the front lip of the seat doesn't collide with the floor when folded up.
IMG_20260709_203536.jpg
Now I installed it all the way to the front. It only just doesn't touch the bridge
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Vertical, for easier getting in/out of passenger
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And down, hanging from the straps (adjustable length to change seat angle)
IMG_20260709_203812.jpg
Seems very comfy :)
 
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Let's not go there again, Flowi. Your tone again rubs me the wrong way and I don't seem to be only one.

You saw I sanded the rollbar down completely (you can see it on many many pictures, not just in post #302, just like the aluminium plate is visible in more than 5 pictures), yet you ask if there's enough adhesion if I laminate over the paint/clear coat.
If you don't look at the pictures carefully at all, then please refrain from asking such questions.
 
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A colleague just texted me that I look really really tired on that picture :LOL:
Yeah... I am.
Have been making long days, working on the bike in evenings and early mornings for a while now.
Maybe I should remove the picture :X3:

it's too late now, 1 hour has passed. It's there forever.. anyway it's not my problem, all of you will just have to look at my tired face :ROFLMAO:
 
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